Veteran defender Malky Mackay scored a rare double and Moses Ashikodi struck on his debut as Watford came from behind to knock Stockport out of the FA Cup.

The visitors looked set to cause an upset when former Manchester United trainee David Poole gave them a 23rd-minute lead, but Mackay levelled seven minutes later and Tommy Smith made it 2-1 in the 48th minute before Mackay made the third-round tie safe with his second goal 14 minutes from time.

Ashikodi - signed from Rangers this week - then took advantage of a bad mistake by County goalkeeper James Spencer to slide in his first Hornets goal six minutes later.

Hornets manager Adrian Boothroyd left Ashley Young - who is likely to be sold to a rival Barclays Premiership club this month - on the bench, with the England under-21 forward brought on midway through the second half.

Stockport had won only two games away from home in Coca-Cola League Two this season, but they could have taken a surprise lead in the first minute.

Watford goalkeeper Ben Foster raced out of his goal to collect a loose ball, but cleared it straight to Poole, whose 30-yard effort was on target but was blocked by Mackay.

Ashikodi thought he had scored when he turned the ball past Spencer from close range after Stockport had dealt poorly with Jordan Stewart's right-wing corner - but the effort was ruled out for offside.

Stockport were saved by the officials for a second time in the 13th minute when referee Lee Probert ruled out Anthony McNamee's fine curling effort from 22 yards for an earlier foul by Damien Francis.

Shortly afterwards, Spencer saved Al Bangura's close-range header after Francis had nodded Stewart's deep corner back into the danger zone.

The visitors survived another scare in the 20th minute when Spencer flapped at Smith's right-wing cross, only for McNamee to see his far-post strike charged down.

Watford were made to rue their missed chances when Tony Dinning released Poole with a fine pass from midfield, and the former Yeovil player - who had timed his run perfectly - beat Foster impressively from the edge of the penalty area in the 23rd.

Watford drew level when Darius Henderson flicked on Smith's 31st-minute corner and Mackay took advantage of poor marking to turn the ball in at the far post.

Stockport brought on Tes Bramble for Michael Malcolm for the second half, but it was Watford who seized the lead with a scrappy goal two minutes after the interval.

Ashikodi cut in from the left and fed Henderson inside the penalty area, before the striker - still without a goal this season - worked the ball to Smith on the right.

The former Derby winger's shot hit goalkeeper Spencer but was forceful enough to trickle into the net for the home side's second goal.

In the 59th minute, Francis should have put Watford two goals clear but scooped the ball over the crossbar from eight yards after Henderson had headed Smith's right-wing cross into his path.

The midfielder's error seemed to give County a lift, and they came close to an equaliser twice in the next five minutes.

First Bramble shot against Foster and then drove the loose ball across goal, before Stephen Gleeson met Poole's right-wing cross with a far-post header which was only just off target.

Stockport sensed they could earn a replay, and brought on their top scorer Adam Le Fondre for Liam Dickinson in the 67th minute.

Watford responded by bringing on Young for Henderson - meaning the former would not be able to play again in the competition should he move on later this month.

Young almost made an instant impact when he glided through the Stockport midfield before unleashing a shot which former Liverpool triallist James Tunnicliffe did well to block.

Watford put the result beyond doubt 14 minutes from full-time when Mackay scored his second goal of the match, sliding in at the far post to convert Stewart's free-kick from the right as the Stockport defence appealed in vain for offside.

McNamee could have made the scoreline more convincing in the 78th minute, but he volleyed well over the bar from a tight angle after County had failed to clear another cross from Smith.

The Hornets did make it four in the 82nd minute when goalkeeper Spencer mis-kicked Bangura's hopeful punt forward in comical fashion, allowing debutant Ashikodi to slide the ball in to get his Watford career off to the perfect start.

Teams:

Watford Foster, Mariappa, DeMerit, Mackay (Doyley 84),Stewart, Smith, Francis (Diagouraga 62), Bangura, McNamee,Henderson (Young 68), Ashikodi.

Subs Not Used: Lee, Powell.

Goals: Mackay 30, Smith 48, Mackay 76, Ashikodi 82.

Stockport: Spencer, Clare, Poole (Le Fondre 69), Owen,Tunnicliffe, Gleeson, Dinning (Rowe 81), Taylor, Griffin,Dickinson, Malcolm (Bramble 46).

Subs Not Used: Deasy, Raynes.

Goals: Poole 23.

Att: 11,745

Ref: L Probert (Gloucestershire).